激光表面处理电梯绳轮的研究

Research on Laser Heat Treatment of Elevator Wheel

采用HL-5000型横流CO2激光加工机,应用宽带技术,选择合适的激光工艺参数,对QT600-3球墨铸铁和40CrMo电梯绳轮进行了激光相变硬化处理。研究了球墨铸铁和40CrMo激光淬火后显微组织的变化,球墨铸铁绳轮基体的显微组织为珠光体、铁素体和球状石墨,激光硬化层的显微组织为石墨球周围一般包围一层等轴状的马氏体和残余奥氏体,其外再围有变态莱氏体层。40CrMo绳轮基体组织为回火索氏体组织,激光硬化层的显微组织为细小马氏体和少量残余奥氏体。测量了淬硬层的性能,淬硬层的硬度可分别达到785HV0.1和767HV0.1,硬化层深度约为0.77 mm和0.75 mm,达到电梯绳轮的技术要求。绳轮实样耐磨性模拟试验表明：激光淬火后耐磨寿命有很大的提高,1987～2007年激光表面处理了电梯绳轮约2万只,全部投入装机使用。

The laser hardening was carried out for QT600-3 nodular cast iron and 40 CrMo steel elevator wheel by using5.0 k W continuous wave CO2 laser,applying the wide-band technology,and choosing right laser-processing parameters.Microstructure of QT600-3 nodular cast iron and 40 Cr Mo laser hardened were researched. Microstructure of nodular cast iron elevator wheel of matrix was pearlite,ferrite and spheroidal graphite,the microstructure of laser hardened layer around the nodular graphite was generally surrounded by a layer of equiaxed martensite and residual austenite,the outer was wrapped with abnormal ledeburite layer. Microstructure of 40 CrMo elevator wheel of matrix was tempering sorbite,microstructure of laser hardened layer was fine martensite and residual austenite. Performance of hardened was tested.The microhardness of hardened reached 785HV0. 1 and 767HV0. 1. Hardened depth was approximately 0. 77 mm and0. 75 mm. Technology demands of elevator wheel were reached. Results of simulated test indicated that the elevator wheel of laser hardened could enhance the wear resistance of original greatly. From 1987 to 2007 a,we made laser surface treatment of the elevator wheel about 20 000,all were installed,users were highly trust.